Report line and column number with errors.

I am trying to use regenerator with jstransform and I am getting the following error when transpiling one of my files:

```
Message:
regenerator error while transforming :
did not recognize object of type "ObjectTypeAnnotation"
```

Lack of line information makes this hard to debug.

Also, I'm trying to use jstransform with `harmony` and `stripTypes` enabled. This does not seem to play so well with regenerator.